1. Field of the Invention
The present invention relates to a clamp structure used to fix a cylindrical member such as a pipe or a hose to another member.
2. Description of the Related Art
Various types of cylindrical members have been used in various types of machines and apparatuses, let alone vehicles, in a variety of applications. For example, an equal velocity joint used as a drive shaft of a vehicle is covered by a cylindrical boot to prevent dust and sand or water from entering or permeating into the joint and grease from leaking from it. A rubber boot is sometimes used in a suspension. Clamp structures are used to fix these boots.
An open type clamp is known as a conventional clamp, as disclosed in U.S. Pat. No. 3,981,049. This clamp comprises a metal band body, a hook formed at an intermediate portion of the band body along its longitudinal direction, a retaining hole for locking the hook, and a rack-like portion extending along the longitudinal direction of the band body. In order to fasten the band body to a surface to be fastened, teeth of a jig having a gear-like rotating portion are meshed with the rack-like portion, and the jig is rotated to reduce the outer diameter of the band body. According to this prior art, in addition to an exclusive tool for fastening the band body, the rack-like portion meshed with a gear-like rotary portion must be considerably long along the longitudinal direction of the band body, resulting in inconvenience.
In closed type clamps disclosed in U.S. Pat. Nos. 3,402,436 and 4,430,775, a lug extends on part of a ring-like band body. When the lug is crushed by a tool such as a nipper, the diameter of the band body is reduced so that the surface to be fastened is actually fastened. Since both ends of the closed type clamp are not separated from each other, it is sometimes difficult to be placed on a surface to be fastened. In addition, since a lug greatly extends on the outer surface of the band body, the lug tends to be brought into contact with an obstacle. When the lug strongly bumps against an obstacle, the lug may be deformed to loosen the band body.